1. Field of the Invention
The present invention relates to a high fidelity loudspeaker system including a multi-driver, electrodynamic loudspeaker designed for consumer and commercial use.
2. General Background
The two largest problems of the electrodynamic loudspeakers of the prior art are, firstly, one driver is unable to reproduce accurately both low and high frequencies, and secondly, as the input power is increased, the distortion rises as well. Both problems stem primarily from the physical limitations of the speaker cone.
In order to be able to reproduce low frequencies, the driver needs the ability to move large amounts of air. In contrast, high frequency reproduction requires very rapid movements of the cone, with much less actual air moving capacity. Large air movement requires the cone either to be very large or move large distances. Movement of the cone (cone excursion) in large amounts, introduces distortion because a cone near its full extension will be unable to reproduce another transient at the same time. So, in order to lower the cone excursion and retain large air movement, the area of the cone is increased. Consequently, when the cone area is increased, so is the mass of the cone. This increase in mass also prevents the cone from traveling properly at the high frequencies of the audio band. The answer to this problem could be simple; viz., separate the audio band into two smaller bands of low and high frequencies, each driving a separate woofer or tweeter, respectively. However, the large woofer lacks adequate transient response in the low frequencies as well as any frequency extending above that point. Although efficient, it requires the use of an enclosure, which because of the interaction of the driver and the cabinet, is tuned to a particular frequency. This is done to increase the overall bass output of the loudspeaker.
Another method of obtaining large cone area is to use the combined effect of several smaller woofers. This offers several advantages, such as: several magnet assemblies (higher efficiency) rather than one large unit, lighter cones for better transient response, and each speaker receives less power and consequently produces less distortion. The concept of multiple-drivers is not new, but because of the inherent phasing and resonance problems of such arrays, their use has been limited.
3. Prior Art
The best prior art known to applicant from a search in the U.S. Patent Office files is listed below -
______________________________________ U.S. Pats. Patentee Pat. No. Issue Date ______________________________________ L. S. Doubt 2,602,860 July 8, 1952 J. E. Parker 2,632,055 March 17, 1953 J. D. Hoffman 2,872,516 February 3, 1959 A. G. Bose 2,915,588 December 1, 1959 M. L. Berry 3,052,758 September 4, 1962 D. Manieri 3,241,631 March 22, 1966 A. G. Bose 3,582,553 June 1, 1971 K. De Boer 2,610,694 September 16, 1952 F. W. Nichols 3,627,948 December 14, 1971 H. Ekdahl, et al. 3,670,842 June 20, 1972 D. Huszty, et al. 3,862,366 January 21, 1975 ______________________________________ "Audio" Magazine Publications P.T.O. Class- Date Pages Article(s) Subclass ______________________________________ November, pp. 20, 21 and "Matrixing" 179-1.GA 1960 77-81 and "Sound System" November, pp. 54, 55 and "The Series- 179-1.GA 1960 99, 100 Parallel Speaker Array" December, pp. 19-22 "Word on Mul- 179-1.GA 1962 tiple Speakers" ______________________________________